This invention relates to downhole data communication in wells where there is a flow of product from the formation towards the surface.
A well in which there is a flow of product from the formation towards the surface is typically called a “producing well” and correspondingly the present application is related to data communication in producing wells.
There are a number of well known data communication techniques for use in wells. Whilst drilling, and during other operations in which mud is circulated through/present in the well, a communication technique known as mud pulsing is sometimes used. This technique has drawbacks and cannot be used in a producing well because of the absence of mud.
On the other hand, there are electrical based techniques either making use of cables passed down into the well or wireless systems and these can be used both during production and at other times. However, these electrical based systems have their own drawbacks. In the case of cable based systems there is the drawback that the cables must be provided down to the transmitting location and there are considerable implementation difficulties, restrictions on range, and power requirement problems for the wireless systems.
Therefore, it is desirable to have alternative data communication techniques for use in producing wells. It is an aim of the present application to provide such alternative techniques.